Portable speaker



FIG. 1 is a top, front and side perspective view of a portable speaker embodying my new design;

FIG. 2 is a bottom, back and side perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof;

FIG. 7 is a first side view thereof; and,

FIG. 8 is a second side view thereof.

Broken lines are used to illustrate features of the portable speaker which form no part of the claimed design. 

CLAIM The ornamental design for a portable speaker, as shown and described. 